Method of supporting plant growth using polymer fibers as a soil substitute

ABSTRACT

The present invention relates to a soil substitute useful in supporting plant growth. More particularly, the present invention relates to biodegradable and non-biodegradable polymer fibers for use in plant cultivation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application was filed under 35 U.S.C. 371 from InternationalApplication No. PCT/US98/26426 filed Nov. 12, 1998 which claims prioritybenefit of Provisional Application No. 60/068,221 filed Dec. 19, 1997,now abandoned.

FIELD OF THE INVENTION

The present invention relates to a soil substitute useful in supportingplant growth. More particularly, the present invention relates tobiodegradable and non-biodegradable polymer fibers for use in plantcultivation.

BACKGROUND OF THE INVENTION

In the conventional cultivation of plants, regardless of being indoor oroutdoor, naturally produced soil has been used as the medium for storingand supplying the nutrients, air, and moisture necessary for raisingplants. It is now well known in the art that artificial media can beused for the germination, rooting and propagation of plants. Media suchas peat moss, vermiculite, perlite, wood bark, sawdust, certain types offly ash, pumice, plastic particles, glass wool, and certain foams arecommonly used, or have been disclosed in the literature, either alone orin various admixtures with each other and/or soil.

Although these prior art media are useful and have achieved commercialacceptance in many areas, they do not provide an optimal balance betweenwater and the gases that can significantly influence root and totalplant growth. It is well known that plants growing in such commonly usedmedia identified above can, under some conditions, suffer from lack ofoxygen or show symptoms commonly believed to be caused by over-watering,i.e., chlorosis, slow growth, pale color, and even death.

U.S. Pat. No. 5,363,593 (Hsh) describes a synthetic cultivation mediumcomprised of fibrous glomerates and a method of manufacturing the same.Absent a soil component, the synthetic cultivation medium ismanufactured from scrap, man-made textiles, chiefly polyacrylonitrile orpolyester fibers. Scrap textile fabrics are shredded into short fibersand chemically refined and bleached. Prior or subsequent to the chemicalrefinement and bleaching, the short fibers are agitated into glomeratesof intertwined fibers. The fiber length is preferably <10 mm, and thediameter of the glomerates is preferably within the range of 2-8 mm.Hsh's uncrimped fiber glomerates are dense and thus wick water more andhold less water than a medium that is less dense. These fiber glomeratesare likely to revert back to fibers upon vigorous or prolonged contact.In addition, the glomerates of Hsh are described therein as nearlyinvulnerable to the degradative effects of natural decomposition.

It is a purpose of the present invention to provide a method ofsupporting plant growth which eliminates or minimizes the plant growthproblems mentioned above.

It is a purpose of the present invention to provide a method ofsupporting plant growth which provides a plant growth medium that, uponthe addition of water and appropriate nutrients, can be used for thegermination of seeds and growth of seedlings, the vegetative propagationand growth of other plant material, and the growth of plants to maturityor some other stage of growth and development.

It is a further purpose of this invention to provide a method ofsupporting plant growth by providing a plant growth medium that that canbe used to replace all or a substantial amount of conventional materialssuch as normal soils, soil mixtures, clay, vermiculite, perlite, peatmoss, bark wood shavings or chips, and the like, thus substantiallyimproving total water holding ability and maintaining a more optimalbalance between solids, water, and gases.

A further purpose of the invention is to provide a method of supportingplant growth which provides a plant growth medium that can bebiodegradable to serve as a soil substitute or a soil supplement forstarting seedlings to be transplanted to fields. Such a medium wouldexhibit considerable water retention and high property retention for aperiod of time prior to transplanting, but would after a certain periodof time thereafter be sufficiently degraded to be “plowed under”.

SUMMARY OF THE INVENTION

The present invention concerns a method of supporting plant growth,comprising contacting plant material with a plant growth mediumcomprising fiberballs in an amount effective to support plant growth,each fiberball consisting essentially of randomly-arranged, entangled,crimped polymer fiber having a cut length of about 0.5 to about 60 mm.

In one preferred embodiment, the plant growth medium comprisesbiodegradable fiberballs prepared from polyester fibers. In anotherpreferred embodiment, the plant growth medium comprisesnon-biodegradable fiberballs prepared from polyester fibers.

DETAILED DESCRIPTION OF THE INVENTION

The present invention concerns a method of supporting plant growth,comprising contacting plant material with a plant growth mediumcomprising fiberballs in an amount effective to support plant growth,each fiberball consisting essentially of randomly-arranged, entangled,crimped polymer fiber having a cut length of about 0.5 to about 60 mm.

Various types of natural and synthetic organic polymer fibers aresuitable for use in the present invention. Synthetic organic polymerfibers are preferred. As used herein, the term “synthetic organicpolymer fibers” includes fibers prepared from polymers such aspolyesters; polyacrylonitrile; polyvinyl alcohol; polyolefins;polyamides, such as nylon; acrylics; polylactides; and the like; as wellas polymers derived from cellulose, such as viscose rayon, celluloseacetate; and the like. Blends of any of the foregoing polymers are alsouseful in the present method, for example nylon and polyester. Preferredsynthetic organic polymers for making fiber useful in the present methodare polyester, polyamide, or blends thereof. Polyethylene terephthalateis most preferred.

The term “natural organic polymers” includes polymers such as wool,cotton, jute, silk, hemp, bagasse, cellulose, and blends thereof.Preferred natural organic polymers are cotton, cellulose, bagasse, andhemp.

The fibers useful in the present invention can comprise hollow or solidfibers and are generally made from polymer fibers in staple form ofvarious cut lengths. The fibers for use in the plant growth medium ofthe method of the present invention generally are staple fibers having acut length in the range of about 0.5 mm to about 60 mm. Siliconeslickeners may be added to the fiber to improve lubricity andaesthetics. Such silicone slickeners are added by coating the fiberswith the slickeners in an amount about 0.15 to about 0.5% Si by weightof the fibers (see U.S. Pat. Nos. 4,618,531 and 4,783,364, incorporatedby reference herein).

The fibers used in preparing the fiberballs herein are crimped. Spirallycrimped fibers, i.e. fibers having a 3-dimensional helical crimp arepreferred. Such crimping can be provided by asymmetric jet-quenching offreshly-extruded filaments, as taught, e.g. in Killian U.S. Pat. Nos.3,050,821 and 3,118,012 incorporated by reference herein, or by themethod disclosed in Evans et al., U.S. Pat. No. 3,671,379, incorporatedby reference herein. Most preferred are spiral crimps in the form of anomega-crimp, as disclosed in U.S. Pat. No. 4,783,364, incorporated byreference herein. Fibers with 2-dimensional saw-tooth crimp induced bymechanical means, such as a stuffer box, can also be used herein.

The polymer fibers are used herein in the form of fiberballs. By“fiberball” is meant polymer fibers which have been formed intosubstantially rounded bodies. The fiberballs preferably have an averagedimension of about 1 to 15 mm, at least 50% by weight of the ballspreferably having a cross-section such that its maximum dimension is notmore than twice its minimum dimension. Polymer fibers in the shape ofsmall, flattened discs mixed with larger cylindrical shapes (referred toas tails) can also be useful in the present method and are included inthe definition of fiberball. There are a variety of methods forpreparing the fiberballs of the present invention including byagitating, rolling, and/or tumbling. Crimped fibers interlock to formvery low density fiberballs having an essentially permanent structure. Apreferred fiberball is formed in accordance with the processes disclosedin detail in U.S. Pat. Nos. 4,618,531 and 4,783,364 which areincorporated by reference herein. The processes involve repeatedlyair-tumbling small tufts of fiber against the wall of a vessel.Generally, any machine capable of agitating fibers to render them stablyentangled can be used to prepare fiberballs useful in the presentinvention. Fiberballs having a cohesion measurement, as defined in U.S.Pat. Nos. 4,618,531 and 4,783,364, of less than about 15 Newtons (15N)are preferred.

Both biodegradable and non-biodegradable organic polymers are suitablefor the polymer fiber useful in the present invention. Non-biodegradablefibers include certain polyesters, polyamides, acrylics, polyvinylacetate, polyacrylonitrile, polyvinyl chloride, and blends thereof.Preferred non-biodegradable polymers are polyester, polyamide, or blendsthereof. Most preferred non-biodegradable polymers are poly(ethyleneterephthalate). COMFOREL® fiber, sold by E. I. du Pont de Nemours andCompany, is preferred as a non-biodegradable fiber for use in preparingthe fiberballs useful in the present invention. Such fiberballs areparticularly suitable in situations where biodegradability is notrequired, such as for use with house plants.

Biodegradable fibers include certain synthetic fibers such as variouspolyesters, and natural fibers such as wool and cotton. A preferredbiodegradable fiber is polyester, and a most preferred polyester is acopolymer of poly(ethylene terephthalate) and diethylene glycol or anon-aromatic diacid, such as adipic acid or glutaric acid, and an alkalimetal or alkaline earth metal sulfo group, such as 5-sulfoisophthalicacid or a metal 5-sulfoisophthalic acid derivative, as disclosed in U.S.Pat. Nos. 5,053,482; 5,097,004; 5,171,308; 5,171,309; 5,219,646; and5,295,985; incorporated by reference herein, and commercially availableas BIOMAX® fiber from E. I. du Pont de Nemours and Company, Wilmington,Del.

The present invention also provides fiberballs comprising biodegradablepolymer fiber having a cut length of about 0.5 mm to about 60 mm, andeach fiberball having an average dimension of about 1 to 15 mm, at least50% by weight of the fiberballs having a cross-section such that itsmaximum dimension is not more than twice its minimum dimension. Thefibers can be coated with a silicone slickener in an amount of about0.15 to about 0.5% Si by weight of the fibers. In addition, the fibersor the fiberballs can be dyed or pigmented. Preferably, the fibers arerandomly-arranged, entangled, and crimped with the fiberballs having acohesion measurement of less than about 15 Newtons. Preferably suchcrimped fibers are spirally crimped, omega crimped or saw-tooth crimped.Such biodegradable fiberballs are preferably prepared from polyesterfiber, most preferably from polyester which is a copolymer ofpoly(ethylene terephthalate) and diethylene glycol or a non-aromaticdiacid, and an alkali metal or alkaline earth metal sulfo group.

A further invention provided herein concerns a process for making suchbiodegradable fiberballs, such process comprising repeatedly tumbling byair small tufts of biodegradable polymer fibers against the wall of avessel to provide an assembly of fiberballs.

The useful life of the plant growth medium useful in the present methoddepends on the type of polymer fiber used and in particular whether ofnot it is biodegradable.

Because easily-dyeable polymers can be used herein, the method of thepresent invention may further comprise contacting said fibers orfiberballs with a dye. The fibers useful in the present invention mayadditionally contain pigments so as to produce colored fiberballs. Thus,the plant growth medium useful in the present method can play a role ininterior decoration.

The method of the present invention pertains to supporting plant growth.By “support” or “supporting” is meant that the medium assists inproviding plant material with a means for subsisting. By “plantmaterial” is meant seeds, germinated seeds, seedlings, sprouts, shoots,tubers, bulbs, plants, or any part of a plant capable of growth on itsown, for example cuttings, or the like.

By “contacting” is meant placing the plant growth medium comprisingfiberballs sufficiently close to the plant material to enable the plantgrowth medium to support plant growth. This can include combining theplant material with the plant growth medium, entangling plant materialwithin a group of fiberballs of the plant growth medium, inserting plantmaterial by hand within a group of fiberballs of the plant growthmedium, placing plant material on top of the plant growth medium,applying additional plant growth medium around or on top of the plantmaterial, combinations thereof, and the like.

The amount of fiberballs used will vary depending on the type and sizeof the plant material and whether the plant growth medium furthercomprises one or more conventional plant medium. For example, the amountof fiberballs initially used to germinate a seed can be a layer only oneor a few fiberballs thick, although thicker layers may be used byapplying additional fiberballs around or on top of the seed. Asurprising small amount of fiberballs can be used in germination (seeExample 1 below). Once a seed has sprouted into a seedling plantadditional fiberballs may be added as needed. The plant growth mediumuseful in the present invention permits good anchoring of the growingroots. When transplanting, the fiberballs around the plant materialremain as a coherent mass making transplanting a facile operation.

A problem with growing plants in pots, in other sorts of indoor growingcontainers, or even in fields is getting adequate water and oxygen tothe roots of the plant. In addition to providing adequate water andoxygen to the roots, the plant growth medium of the present method canexhibit many features and advantages, some of which may depend in parton the type of fiber selected for use in preparing the fiberballs usedherein: resistance to decay or biodegradable, resistance to microbes,lightness, and a morphology and density particularly conducive to plantgrowth.

The poor water retention properties of conventional plant media make itnecessary to be selective with regard to the type of grain or plant tobe cultivated, and the number of times it needs to be watered would needto be increased. However, the plant growth medium useful in the presentmethod has very good moisture retention characteristics. For example,fiberballs prepared from COMFOREL® can absorb up to 30 times theirweight in water. Good drainage is also evident from the method of thepresent invention.

Because of its unique morphology, large quantities of air are retainedbetween the fiberballs, and thus the plant growth medium useful in thepresent method provides adequate amounts of oxygen to the roots. Inaddition, this morphology enables good thermal insulation.

Conventional plant growth media are watered from the top and kept out ofexcess water to prevent water wicking to their top surfaces. Water onthe top surface of a plant growing media will often kill a seedling viaa process known as “damp off.” Another highly useful attribute of thefiberballs useful in the present method is that they do not appear towick water to the surface (see Example 4 below), thus offering thepotential to reduce evaporation losses. By not wicking water to theirtop surfaces, the fiberballs useful in the present invention enableswatering plants from the bottom. However, the structure of thefiberballs make possible sufficient capillary action for retainingliquids close to plant roots. Such a quality promotes the growth ofprosperous and well-developed plant root systems and enables the use ofthe present method in hydroponic systems.

Environmental harm to rivers and streams is reduced by using the presentmethod because nutrients are adsorbed and retained by the plant growthmedium and not washed away by rain. In addition, no more fertilizer thannecessary need be provided using this method. Thus, the fiberballs,preferably the biodegradable fiberballs of the present invention, can beused in “precision farming.” By “precision farming” is meant a farmingmethod wherein a seed, cutting or seedling is placed into the groundalong with a precisely placed addition of nutrients, pesticides, etc.The advantage provided by precision farming is it avoids the surfaceapplication of agricultural chemicals that ultimately are washed awayinto the water table. Using the biodegradable fibers of the presentinvention together with conventional plant growth material provides aconvenient method for precision farming wherein the agriculturalchemicals can be added together with the fiberballs or can be applied tothe fiberballs after the plant material and fiberballs are placed in thegroup.

Because plants can be cultivated without using any natural soil at all,the plant growth medium of the present method can be hygienic. Becausecertain embodiments of the plant growth medium of the present method areprepared from synthetic fibers, the medium can be sterile and can beparticularly suited for growing sensitive plants.

When prepared from synthetic polymer fibers, the fiberballs of the plantgrowth medium can be resistant to microbes and thus less susceptible tobacterial, viral, fungal and insect infestation. Thus, utilization ofsuch plant growth medium would alleviate the need to use environmentallyhazardous fungicides, insecticides or other infestation controllingchemicals and make more desirable distribution of plants marketed intactwith root systems.

The plant growth medium of the present invention is particularlysuitable for use as a growth medium for seed germination testing.Nurseries test seed germination rates and are confronted with thedifficulty of finding consistent, reproducible growth media.Conventional growth media vary due to different points of origin as wellas due to aging effects. For example, organic material such as peat mossdegrades over time giving a higher acid content. The fiberballs of thepresent invention overcome these difficulties by providing a sterile,consistent growth medium for seed germination testing.

Once a crop has been harvested, biodegradable plant growth medium usefulin the present invention is much more suitable for composting due to itsdegradable nature. Biodegradable fiberballs can be used in a field asneeded and readily plowed under because they would physically comeapart. The individual fibers of the fiberballs can be allowed to degrademore slowly since degradation would no longer be required to achieve the“plowed under” capability.

The comparative light weight of the fiberballs useful in the presentinvention makes them especially suitable for cultivation in specialregions, such as mountains or the coast, infertile natural environments,or urban areas. In the urban environment, the light weight of thefiberballs makes them particularly suitable for cultivating plants inrooftop gardens, terraces, and balconies. Standing in marked contrast tocomparatively heavy soil, the light weight. of the fiberballs alsocontributes to their ease of transport, and manipulation. Consequently,the back-breaking toil often associated with tilling and preparing farmland is avoided. In addition, the fiberballs provide better airavailability and higher water holding capacity than other lightweightsynthetic soils such as those made of polystyrene foam. Further, thefiberballs are safe to handle and can be stored substantiallyindefinitely.

Although fiberballs in themselves contain no available sources of plantnutrition, they do demonstrate good nutrient adsorption characteristics.Thus, the method of the present invention can further comprisecontacting said plant growth medium, said plant material, or both, withat least one plant adjuvant. Contacting via spraying, dipping,irrigating, and/or the like with a balanced nutrient liquid is easilyachieved in accordance with known hydroponic, agricultural, orhorticultural principles. Likewise, the method of the present inventioncan further comprise providing light as needed to foster growth.

One benefit of providing plants with nutrients hydroponically is thatthe problems associated with soil depletion and decomposition areavoided. Other costly traditional means of farming, such as croprotation, are also avoided.

Water-soluble adjuvants for use in preferred embodiments of the presentinvention include nutrients, fertilizers, fungicides, algaecides, weedkillers, pesticides, hormones, bactericides, plant growth regulators,insecticides, combinations thereof, and the like. Numerous water-solubleplant fertilizers or nutrients are available commercially. Suitablefungicides include benomyl and other benzimidazoles (e.g. Benlate® soldby E. I. du Pont de Nemours and Company), flusilazole and othertriazoles (e.g., Nustar® sold by E. I. du Pont de Nemours and Compny,metalaxyl and other acylalanines (e.g., Ridomil® sold by Ciba-GeigyCorp.), and tridemorph and other morphlines (e.g., Calixine® sold byBASF), among others. Suitable insecticides include oxamyl and otherrelated carbamates (e.g., Vydate® sold by E. I. dupont de Nemours andCompany), acephate (e.g. Orthene® sold by Chevron Chemical Co.),resmethrin and other pyrethrodis (e.g., Synthrine® sold by FairfieldAmerican Corp.), among others. Suitable herbicides include chlorsulfuronand other sulfonylureas (e.g., Glena® sold by E. I. du Pont de Nemoursand Company) among others. Combinations of fungicides, insecticides andfertilizers help protect young germinating seedling plants from diseaseand insect damage while supplying needed nutrients.

The plant growth medium useful in the method of the present inventioncan further comprise at least one conventional plant growth medium. Suchconventional plant growth media include natural soil, soil mixtures,vermiculite, sand, perlite, peat moss, clay, wood bark, sawdust, flyash, pumice, plastic particles, glass wool, and polyurethane foams, andcombinations thereof.

With the growing demand for soil for plants used as decoration for roominteriors and cultivated on balconies or rooftops, particularly urbanareas, the present invention is useful in providing a plant growthmedium as a soil substitute, including for hydroponic cultivation, as asoil supplement in flower pots, balcony planters, or in rooftop areas tocultivate plants, or as a supplement to other conventional plant growthmedia. In addition, by increasing the scale, the present method can alsobe used for processed horticulture and in raising grain.

EXAMPLES

In the examples below the following media were used: dry fiberballs,slick fiberballs, bio fiberballs, peat moss, and Metromix 360. The dry(unsized) fiberballs were COMFOREL® polyethylene terephthalate (PET)fiberfill obtained from E. I. du Pont de Nemours and Company. The slickfiberballs were COMFOREL® PET fiberfill wherein the fibers had beencoated with a silicone slickener sizing. The slick fiberballs used inExample 1 are a different lot than those of the other examples. TheExample 1 slick fiberballs have a higher bulk density. The biofiberballs were prepared from BIOMAX®, subjected to mechanical saw-toothcrimping, followed by the fiberball construction processes disclosed inU.S. Pat. Nos. 4,618,531 and 4,783,364. The Canadian Sphagnum peat mosswas obtained as a three cubic foot bag and was produced byASB-Greenworld, Inc., P.O. Box 1728 Valdosta, Ga. 31603. The Metromix360 growing medium is a combination of soilless mix ingredients ofchoice cut milled Canadian sphagnum peat moss, No. 3 grade horticulturalvermiculite, tested wetting agents, starter nutrient charge, coarserhorticultural perlite, selected washed granite sand and processed barkash. The Metromix 360 is commercially sold and was obtained from E. C.Geiger, Inc., Harleysville, Pa. 19438.

Example 1

This experiment demonstrates the germination of seeds and theirsubsequent growth into plants in plant growth medium useful in thepresent method compared to peat moss.

Small rectangular poly(styrene) planters were used to plant twenty Wyesoy bean and Rutgers tomato seeds each in each of the following media:slick fiberballs and Canadian Spaghnum peat moss (as received). Theseeds had been refrigerated for storage with the Wye bean seeds dated1989 and the Rutgers tomato seeds (lot 0620121006F) dated 1988. A volumeof 57 milliliters was the target fill for the planters. An average of2.19 grams of slick fiberballs and 19.9 grams peat moss was used to fillthe planters. The seeds were placed ½″ beneath the surface of theplanting media. The planters were placed in two trays, tomatoes in onetray and Wye beans in the other. Within each tray the planters werepositioned in alternating rows of each of the two different media. Thetrays containing the planters were placed in a greenhouse where theywere watered from above on Monday, Wednesday and Friday with a nutrientsolution. Ultimately, 11 Wye beans and 9 tomatoes grew in the slickfiberballs. No plants grew in the peat moss; however, a green substance(presumably algae) grew on the peat moss, and due to splashing duringwatering spread to the slick fiberballs.

Wye soy bean and tomato plants exceeding one foot in height grew in theslick fiberballs and were self supporting. The plants could be pulledfrom the planters and all of the slick fiberballs remained with theroots. Transplanting into larger planters was done easily by adding moreslick fiberballs to the larger planter, positioning the plant with itsoriginal fiberballs in the center of the new larger planter, and addingmore slick fiberballs around the sides of the plant. Transplanting withslick fiberballs was an easy and clean task.

Upon examination, the plant roots were found to be concentrated in thebottom of the planters with little or no root growth in the upper halfof the slick fiberballs. Planters containing a Wye bean plant and atomato plant were placed in a tray and a water level in the tray halfway up the planters was maintained. Roots then grew throughout theheight of the slick fiberballs for both types of plants.

Seeds germinated and grew in the slick fiberballs with surprisinglylarge plants growing in a relatively small amount of fiberballs. Theplants could be removed from the planter, and the fiberballs remained acoherent mass (making transplanting a facile operation). It was foundthat the water level outside the planters could be adjusted to affectsecondary root growth in plants cultivated with the slick fiberballs.

Example 2

This experiment demonstrates the germination of seeds and theirsubsequent growth into plants in plant growth medium useful in thepresent method compared to peat moss.

Ten Silver Queen Hybrid Corn seeds (NKLawn and Garden Company,Chattanooga, Tenn. packed for 1997 Lot 2) were planted in rectangularplanters containing approximately 50 milliliters of dry fiberballs(average weight 1.31 grams), slick fiberballs (average weight 1.17grams), and as received peat moss (average weight 16.17 grams). Theseeds were planted ½″ beneath the surface of the planting media. Theseeds were watered with 15 milliliters of demineralized water containingliquid plant food (8:7:6 of nitrogen/phosphate/potash, respectively, at10 drops per liter water). Watering was done three times per weekthereafter.

The corn plants growth measurements 13 days after seed planting appearin Tables 1 and 2. Four corn seeds germinated and grew in each of theplanting media. Plant heights above the top surface of the growth mediawere measured. Plant stalk breadths were measured at their largest valueabove the plant growth media, but below leaf growth. Table 2 gives thenumber of leaves on each of the four corn plants growing in the threedifferent media. In Table 2, if the plant had not unfurled its leaves itwas designated as “shoot”. The maximum leaf widths were measured foreach type of growth media.

TABLE 1 Corn Growth Results in PET Fiberballs and Peat Moss Media PlantHeight (cm)/Stalk Breadth (mm) Dry fiberballs 18.5/3.0  17.2/3.0 14.2/2.5  11.2/2.5  Slick fiberballs 0.8/2.5 1.2/2.0 8.5/2.5 5.4/2.0Peat moss 0.8/1.0 1.5/2.0 9.3/2.0 7.0/3.0

TABLE 2 Corn Leaf Growth Media Number of Leaves Maximum Leaf Width (mm)Dry fiberballs 3/3/3/3 13 Slick fiberballs shoot/shoot/2/3 10 Peat mossshoot/shoot/2/1  9

The data of Tables 1 and 2 clearly show dry fiberballs gave superiorgrowth to peat moss. Comparing the corn plants in slick fiberballs andpeat moss, those growing in the slick fiberballs appeared hardier.

Example 3

This experiment demonstrates the water retention of plant growth mediauseful in the present method compared to conventional plant growthmedia.

Six 100 milliliter Nalgene poly(propylene) beakers (model number1201-0100) having ¼″ diameter holes in the center of their bottoms werefilled to 50 milliliters with the following media: dry fiberballs, slickfiberballs, bio fiberballs, Metromix 360, and peat moss. The beakerscontaining media were placed on top of an elevated wire rack to allowfree drainage. To each of these beakers 100.0 milliliters ofdemineralized water was poured. The pouring of the 100 milliliteraliquots was done rapidly for all types of fiberballs; however, theslick fiberballs were held in place with two fingers because of theirtendency to float. The 100 milliliter water additions to the Metromix360 and peat moss were done slowly to prevent loss of the media throughthe hole in the beaker bottom. After addition of the 100 milliliters ofwater, the beakers containing the fiberballs were tilted to pour off anywater that would leave. This pouring sometimes caused the wet mass offiberballs to compress, much like the reaction of squeezing a sponge. Asan example, the slick cluster retained 32.1 grams water per gramfiberballs prior to pouring off the water. Little attempt was made topour water off the Metromix 360 or peat moss to prevent pouring off themedia themselves, though excess water was clearly visible. Peat mossthat had been thoroughly dried does not wet with the water.

Table 3 presents water retention data for the five different media. Peatmoss as received and dried were both evaluated. The Metromix 360 and asreceived peat moss data are presented below as water retained on a drymedia basis since these media initially contained 43.5% and 70% byweight water, respectively. The fiberballs contained less than onepercent water initially, so no correction for initial water content wasmade.

TABLE 3 Water Retention of Various Media Dry Media Water Retained (gWater/g Media) Media wt. (g) 1 Hr 2 Hr. 20 Hr. 52 Hr. 192 Hr. Dryfiberballs 0.87 36.2 34.5 32.7 28.5 16.3 Slick fiberballs 0.57 17.4 15.413.0 9.91 dry Bio fiberballs 1.88 19.0 18.2 17.2 15.2 8.81 Metromix 36010.19 2.80 2.76 2.59 2.18 0.95 (5.67 g + 4.43 5.72 5.65 5.36 4.66 2.46 gwater) Peat moss 14.02 1.95 1.60 1.81 1.51 0.56 (as received) (4.21 g +9.81 8.84 8.77 8.38 7.36 4.21 g water) Peat Moss (Dried) 6.49 Did NotWet

The data of Table 3 illustrates that the fiberballs have a high degreeof water retention relative to conventional plant growth media.

Example 4

This experiment demonstrates the water wicking characteristics of plantgrowth media useful in the present method compared to conventional plantgrowth media.

The same type of beaker and the same five media as described in Example3 were used. Two beakers were filled to 50 milliliters of each of thefive growth media, and placed in a tray containing enough water to coverthe 10 milliliter line on each beaker. Within 30 minutes the water hadwicked to the top of the Metromix 360 and peat moss top surfaces. Thebeakers were removed from the water, their outside sides and bottomsdried and then weighed after 1 hr, after 18 hr, and after 50 hr. Theslick fiberballs were floating atop the water for the 1 hour weighing.

Table 4 presents water wicking data for the five different media. Thedata for the Metromix 360 and peat moss were corrected for theirrespective dry weights.

TABLE 4 Water Wicking of Fiberballs and Conventional Plant Growth MediaWater Dry Wicking Media Height Water Retained (g Water/g Media) MediaWt. (g) (% Wet) 1 Hr. 18 Hr. 50 Hr. Dry fiberballs 0.81 40 16.0 16.816.7 Slick fiberballs 0.63 20 3.08 9.38 9.40 Bio fiberballs 1.88 80 14.514.2 13.8 Metromix 360 13.30  100 2.30 2.31 2.27 (7.51 g + 5.79 4.854.86 4.79 g water) Peat moss 14.52  100 1.52 1.68 1.63 (as received)(4.36 g + 10.16 7.40 7.94 7.72 g water)

As shown in Table 4 above, the fiberballs wicked water to varyingdegrees depending on whether they possessed the silicone sizing or not.In either case, the fiberballs did not wick water to their top surfacesas did conventional plant growth media.

Example 5

Comparison of Cluster Water Retention vs Conventional Plant Growth Media

This experiment demonstrates that fiberballs can be packed into planterpots at various densities in order to obtain a desired level of waterretention.

Planter pots having a volume of 55 cm³ were filled with variousconventional plant growth media and fiberballs compacted to differentdensities. The conventional plant growth media filled the planterswithout compaction. The conventional plant growth media were those onhand in a greenhouse, and were in a condition to be used for plantingwithout any additional treatments. An excess of water was poured intothe filled planters and the weight of water retained recorded. Table 5below lists the average weight of water retained for six trials.

The data below shows the fiberballs capable of retaining water amountscomparable to or exceeding those of conventional plant growth media.

TABLE 5 Growth Media Density (g/cm³) Water Retained (g) Dry fiberballs0.05 36 0.07 41 0.10 45 0.13 48 Slick fiberballs 0.01 07 0.05 24 0.07 280.10 33 0.13 40 Sphagnum moss 0.03 22 Vermiculite course 0.09 21Vermiculite fine 0.09 27 Perlite 0.10 16 Rockwool compote 0.12 26Rockwool 0.07 29 Metro-mix 200 0.18 28 Metro-mix 360 0.21 24 Perlitesuper course 0.13 14 Metro-mix 510 0.24 22 Metro-mix 300A 0.24 23

What is claimed:
 1. A method of supporting plant growth, comprising:contacting plant material with a plant growth medium comprisingfiberballs in an amount effective to support plant growth, eachfiberball consisting essentially of randomly-arranged, entangled,crimped polymer fiber having a cut length of about 0.5 to about 60 mm.2. The method of claim 1 wherein the fiberballs have a cohesionmeasurement of less than about 15 Newtons.
 3. The method of claim 1wherein the fiberballs have an average dimension of about 1 to 15 mm, atleast 50% by weight of the fiberballs having a cross-section such thatits maximum dimension is not more than twice its minimum dimension. 4.The method of claim 1 wherein the fibers are spirally crimped.
 5. Themethod of claim 1 wherein the fibers are omega-crimped.
 6. The method ofclaim 1 wherein the fibers are saw-tooth crimped.
 7. The method of claim1 wherein the fibers are dyed or pigmented.
 8. The method of claim 1wherein the polymer fiber is prepared from a synthetic,non-biodegradable polymer.
 9. The method of claim 1 wherein the fibersare coated with a silicone slickener in an amount of about 0.15 to about0.5% Si by weight of the fibers.
 10. The method of claim 9 wherein thepolymer is selected from the group consisting of: polyester, polyamide,and blends thereof.
 11. The method of claim 10 wherein the polymer ispolyester.
 12. The method of claim 1 wherein the polymer fiber isprepared from a synthetic, biodegradable polymer.
 13. The method ofclaim 12 wherein the polymer is polyester.
 14. The method of claim 13wherein the polyester is a copolymer of poly(ethylene terephthalate) anddiethylene glycol or a non-aromatic diacid, and an alkali metal oralkaline earth metal sulfo group.
 15. The method of claim 1 wherein theplant material is a seed.
 16. The method of claim 1 further comprising:contacting said plant growth medium, said plant material, or both, withat least one plant adjuvant.
 17. The method of claim 16 wherein the atleast one plant adjuvant is precisely applied.
 18. The method of claim16 wherein the plant material is cultivated hydroponically.
 19. Themethod of claim 1 wherein the plant growth medium further comprises oneor more convention plant medium selected from the group consisting ofnatural soil, soil mixtures, vermiculite, sand, perlite, peat moss,clay, wood bark, sawdust, fly ash, pumice, plastic particles, glasswool, polyurethane foams, and combinations thereof.